Both 9mm and 12 gage slug has over peneration
For home defence with children in the house I use a short 12 gage pump shotgun (postol grip) with bird shot. Thats right BIRD SHOT
In side of 10 feet there is little difference from a slug and will quickly loose energy through two layers of drywall.
If you hit some one center mass with a 12 gage bird shot as 10 feet that person is not going to do much other than fall down.
If there are hostages, the best thing is to call poliece and let some one that is trained in working with the problem, your just going to get your loved ones killed.
A 223 is the worst weapon you could use in a house with others, your neighbors are also in danger.
One of the other advantages of a 12 gage pump, the noise of loading a pump will put the scare in to mose people.
And stay away from Hi-point firearms the only good thing I can say about them is that they are cheep.
I have sold them, and fired them, cheep thats all they are. They cant hold a candle to a beretta storm carbine even at 1/3 times the price.